The safety lapses didn't result in any fatalities, but the two separate close calls over the past few weeks have prompted renewed scrutiny of pilot attentiveness by government regulators and crash experts. The latest investigations follow a string of other cockpit mistakes—some stretching back to 2009—highlighting the dangers of pilot complacency or distraction.

On August 26, a JetBlue Airways Airbus A320 blew four tires and experienced a landing-gear fire after touching down in Sacramento, Calif. Seven of the 86 passengers aboard the plane, en route from Long Beach, Calif., received minor injuries during the emergency evacuation on the runway.

Investigators subsequently determined that the pilots of JetBlue Flight 262 inadvertently engaged the plane's parking brake while approaching the airport at roughly 5,000 feet. According to preliminary findings of the National Transportation Safety Board, the first officer was at the controls when the plane touched down and "began a rapid deceleration." Four main landing gear tires deflated and main wheel rims were damaged.

Similar parking brake slip-ups have occurred on a number of other Airbus aircraft over the years, according to pilots, even though the planes are designed to alert the crew whenever the parking brake is engaged. The safety board said neither pilot "recalled any abnormal indications or warnings" of braking system problems prior to landing.

A JetBlue spokesman said the carrier was cooperating fully with the safety board, but he declined further comment.

The Allegiant Air incident involved a McDonnell Douglas MD-82 jet that barely managed to take off from the Lake Charles, La. airport less than two weeks later. The plane damaged part of its landing gear after using the entire strip for its takeoff roll, and then striking lights at the end of the runway. The pilots, who apparently didn't realize the damage until they were alerted by air-traffic controllers, diverted and landed safely in Tunica, Miss. Allegiant Air's parent is Las Vegas-based Allegiant Travel Co.

An Allegiant spokeswoman declined to comment, except to say the airline was cooperating with investigators. An FAA spokesman declined to comment on the status of the agency's probe.

Federal regulators, safety-board investigators and pilot-union leaders appear particularly sensitive to suspected cockpit distraction after some high-profile examples. The most prominent incident occurred in October 2009, when the pilots of a Northwest Airlines jetliner cruising at 37,000 feet across the country lost radio contact with controllers for more than an hour. The plane overshot Minneapolis, its destination airport, by roughly 100 miles, before the cockpit crew realized the mistake.

Both pilots told investigators they became distracted talking about changing crew schedules and looking at a personal laptop opened on the flight deck.

The errant flight resulted in a Congressional outcry, stoked public outrage and led to FAA moves to revoke the licenses of the pilots. Ultimately, both pilots left the airline, which is now part of Delta Air Lines Inc.

Pilots "simply cannot allow complacency and inattention to permeate and contaminate cockpits." Rory Kay, a top safety official at the Air Line Pilots Association, said during a recent public safety forum. Aviators must "comprehensively self-assess their fitness to fly," according to Capt. Kay, who flies for United Airlines.

A week before the Minneapolis incident, an experienced Delta crew on an overnight flight from South America landed a widebody Boeing 767 on a 75-foot wide taxiway instead of a parallel, 150-foot wide runway at Atlanta's Hartsfield International Airport.

The weather and visibility were both good, and runways have different colored lights than taxiways. But investigators determined that at the end of a 10-hour flight from Rio de Janeiro, the crew was distracted by the illness of a senior pilot, several different landing instructions from controllers and the desire to taxi as quickly as possible to the terminal.

Between the fall of 2009 and the spring of 2010, pilots for two U.S. commuter airlines failed to start up the second engines of their jets before getting ready to take off. The unusual incidents prompted federal investigations and sparked comments by safety experts about the need to step up training to prevent pilot distractions that can result in dangerous errors. Both crews realized the mistake before their aircraft started to gain speed.

There also have been scores of pilot mistakes that escaped public notice. During 2008 and 2009, at least 20 crews flying for Comair, Delta's commuter arm, prepared to take off without extending the Canadair regional jet's flaps, movable panels at the rear of the wings essential to enhance lift. In each case, according to people familiar with details, automated cockpit warnings sounded before takeoff and there were no accidents. But the airline felt the need to rewrite parts of its checklists and review training procedures to assure proper flap deployment.

A Comair spokeswoman said Wednesday that the carrier's safety-reporting program "identified the need to reinforce the new procedure, and since that time, we have experienced no further incidents."

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